The Subgroup Structure

Contents

General Subgroup Constructions

The operators and functions which construct a subgroup of a polycyclic group always return the subgroup as a polycyclic group.

H ^ g : GrpGPC, GrpGPCElt -> GrpGPC
Conjugate(H, g) : GrpGPC, GrpGPCElt -> GrpGPC
Construct the conjugate g - 1 * H * g of the group H under the action of the element g. The group H and the element g must belong to a common group.
H ^ G : GrpGPC, GrpGPC -> GrpGPC
ncl< G | H > : GrpGPC, GrpGPC -> GrpGPC
NormalClosure(G, H) : GrpGPC, GrpGPC -> GrpGPC
Given a subgroup H of the group G, construct the normal closure of H in G.
CommutatorSubgroup(G, H, K) : GrpGPC, GrpGPC, GrpGPC -> GrpGPC
CommutatorSubgroup(H, K) : GrpGPC, GrpGPC -> GrpGPC
Construct the commutator subgroup of groups H and K, where H and K are subgroups of a common group G.

Subgroup Constructions Requiring a Nil-po-tent Covering Group

The operators and functions described in this section require the existence of a nilpotent covering group. They are based on algorithms published in [Lo98]. Again, the constructed subgroup is returned as a polycyclic group.

H meet K : GrpGPC, GrpGPC -> GrpGPC
Given two groups H and K, contained in some common group G which is nilpotent, construct the intersection of H and K.
H meet:= K : GrpGPC, GrpGPC -> GrpGPC
Given two groups H and K, contained in some common group G which is nilpotent, replace H with the intersection of H and K.
Centraliser(G, g) : GrpGPC, GrpGPCElt -> GrpGPC
Centralizer(G, g) : GrpGPC, GrpGPCElt -> GrpGPC
The subgroup of G centralising g. Both g and G must be contained in some common nilpotent group.
Centraliser(G, H) : GrpGPC, GrpGPC -> GrpGPC
Centralizer(G, H) : GrpGPC, GrpGPC -> GrpGPC
The subgroup of G centralising H. Both H and G must be subgroups of some common nilpotent group.
Core(G, H) : GrpGPC, GrpGPC -> GrpGPC
The maximal normal subgroup of the nilpotent group G that is contained in the subgroup H of G.
Normaliser(G, H) : GrpGPC, GrpGPC -> GrpGPC
Normalizer(G, H) : GrpGPC, GrpGPC -> GrpGPC
The subgroup of G normalising H. Both H and G must be subgroups of some common nilpotent group.
V2.28, 13 July 2023